In recent years, in order to realize miniaturization, cost reduction and the like of display devices, there have been progressed developments of display devices that have a display unit including pixel circuits and a gate driver for driving gate bus lines (scanning signal lines), formed on the same panel substrate. In such a display device, a gate driver is provided in the display panel. Therefore, such a display panel is called a GIP (Gate In Panel).
Regarding a display device that includes a GIP, a configuration that makes it possible to perform changeover (reversal) of a scanning order of gate bus lines is known. The changeover (reversal) of a scanning order is to perform changeover between normal-order scan of driving gate bus lines one by one from one end (an upper end, for example) of the display unit to the other end (a lower end, for example) of the display unit, and reverse-order scan of driving gate bus lines one by one from the other end of the display unit to the one end of the display unit. For example, in a display device that includes n gate bus lines as shown in FIG. 17, the gate bus lines are scanned in the order of “a first row, a second row, a third row, . . . , an (n−2)-th row, an (n−1)-th row, and an n-th row” in normal-order scan, and the gate bus lines are scanned in the order of “the n-th row, the (n−1)-th row, (n−2)-th row, . . . , the third row, the second row, and the first row” in reverse-order scan. It should be noted that to change over a scanning order between a normal order and a reverse order in this way will be hereinafter referred to as “scanning order reversal”. With the display device that can perform such scanning order reversal, even when a television is installed by being hanged from the ceiling, for example, it becomes possible to enable viewers to watch an image in a correct direction, by performing of reverse-order scan.
It should be noted that, in relation to the present invention, Japanese patent Application Laid-Open No. 2004-117742 discloses an invention relating to a display device that can reduce bias current of an output buffer.